Tuesday, June 9, 2009

VMware or Citrix?

Citrix released their virtualization solution named XenServer (from version 5, article XenServer is free) for free but only the time will show if it was a right decision. At first glance, it seems like a marvelous thing but there are some facts which should be investigated first. Together with XenServer, it was released central management solution XenCenter.

Let's have a look at their rival VMware (vSphere 4). XenServer is fully comparable to VMware ESX or ESXi. But what about XenCenter management? It's something more than VMware vSphere client but not so valuable as VMware vCenter Management Server. Citrix XenCenter is not the right choice in case of comparison to vCenter. The right one is Citrix Essentials but this one is not for free already. The main differences between Citrix XenCenter and Essentials are:

XenCenter is missingalerting capabilities like send me an email when "CPU usage is too high" or when some error condition like "virtual machine power on failure" appears

XenCenter is missing high availability support

XenCenter is not able to show you performance data older than one day for physical or virtual servers

Now, let's try to propose a simple high availability (HA) solution based on Citrix/VMware products and compare their prices. Let's suppose we have 2 (3) entry level servers where each have 2 CPUs with max 6 cores per CPU (6 CPUs total). The servers are connected to a shared disk storage. The CPU speed or memory capacity is not important now. And we require HA solution to protect our virtual machines from hardware failure. Follows the analysis:

The prices of proposed solutions are quite different. In my opinion, the most valued solution is based on new VMware product line vSphere 4 Essentials.

There are rumors that VMware is the most expensive solution. I don't think so if I check the numbers above. Citrix's solution not covered by support is cheaper then VMware's solution with support but only for 2 servers. If I would like to add third server I would have to pay another license in case of Citrix. In case of VMware, I have still one spare license so I will use it. At first glance, XenServer seems to be free of charge but the price of added value by Citrix Essentials doesn't scale as well as in case of VMware vSphere 4 Standard Edition or vSphere 4 Essentials Plus. And what is your opinion to the topic?

5 comments:

Anonymous
said...

Funny how you decided to write about the one case -- three nodes, no more, no less; HA is the only important charged-for feature, not smart storage, not workload balancing, not even motion which many users say is more fundamental -- on which VMware's pricing looks remotely decent. They paying you?

I would encourage you to consider the following points to make your comparison a bit more thorough:

1. Essentials for XenServer-Enterprise costs $2500 per server. Essentials for XS-Platinum is $5000 per server

($5550 was the price for a short period of time when the US dollar was weak)2. The XenServer-based solution you cited (Platinum) includes Lab Manager and stage Manager. If you want to do

a fair comparison, you should include the additional fees for these procudts on the VMware side (which are not part of any vSphere edition)3. Essentials for XenServer-Enterprise includes live migration and VM workload balancing. vSphere standard does

not have either of these features. vSphere Advanced Edition is required for vMotion, and vSphere Enterprise is required for DRS. These are $2700 and $3500 per processor, so you are looking at 2-3x the price of XenServer if you want these features in your deployment.4. VMware charges per processor. Citrix charges per server, regardless of whether the server has 2, 4, 8,

processors. If you want to use 4 processor servers and get higher consolidation ratios, XenServer is *much*

less expensive. VMware, by contrast, penalizes use of more powerful servers by charging per-processor.4. Comparing at 3 servers is interesting for some, but what happens when you need that fourth server? vCenter 4

foundation no longer applies, and the 3-server bundles aren't applicable5. VMware and Citrix have different support models. One isn't necessarily better than the other. Citrix

charges based on the number of cases per year. VMware increases the support costs based on the number of

servers. It's an apples-to-oranges comparison. If you have a larger environment, Citrix's is arguably more

cost-effective. In a very small environment, VMware might be more cost-effective if you plan to open a lot of

solution costs $20,250 over a 3 year period (including suport). This is based on Essentials for

XenServer-Enterprise Edition. With this you get Provisioning Services, a feature that has nothing compariable in the Vmware world and is useful for Terminal Server, Citrix XenApp, and web server farms.

For a VMware solution with similar functionality, you would need vSphere Enterprise Edition and the 3 year costs

would be $118,173 (including Gold support). This includes vCenter and vCenter server heartbeat. This is so

much more expensive because VMware charges per processor, and results in it being almost 6x the cost of a

XenServer solution. To be fair, this solution includes the storage vMotion, which Citrix XenServer doesn't currently have.

Another example: A 20-server Xenserver solution based on 2-processor servers with HA, live migration, and VM workload balancing costs around $67,500 over 3 years. VMware is around $211,913 over 3 years- 3x the cost of XenServer.

Thank you for your opinion. I'm going to prepare more comparisons as I seem to prefer only VMware solution.

If I presumed the solution should be HA capable only I don't need live motion or DRS. What if customer doesn't want to pay for it? I want just HA and VMware knows that there are many such customers with thin budget who can't afford more and who don't need it.

By the way, DRS is part of XenServer 5.5 which was released recently and I suppose it will take a while until it will be as useful as VMware's DRS.

I agree XenServer have higher consolidation ratio as it is based on Xen hypervisor and it is based on paravirtualization which has lower overhead and so higher ratio.

I agree that comparing support models of both companies is difficult but I just want to include support in the comparison.

David, Also it would be fair to compare entry levels and most common features..Citrix Xen offers you Live motion, cloning and management with Xencenter for free while VMware gives you ESXi (only hypervisor).In addition DRS capabilities and HA most of the time are managed at application levels ...instead of infrastructure levels...

About Me

My name is David Sumsky and I'm working as a UNIX system engineer. I'm in charge of designing, installing and maintaining solutions based on UNIX platform. The purpose of this blog is to share my knowledge and experience with other people who are interested in similar topics like me. If you want to contact me you can write at dsumsky at gmail.com